Frequency converter



FIG. 1 is an isometric front perspective view of a frequency converter;

FIG. 2 is a front view thereof;

FIG. 3 is a right view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof. 

CLAIM The ornamental design for a frequency converter, as shown and described. 